The present invention involves a system and method for fabricating a prosthetic limb cosmetic cover, and more particularly to a system and method for substantially completely automating the process of fabricating the cosmetic cover.
A prosthesis is often used to replace an amputated portion of the limb and to help restore the amputees ability to use that limb. A prosthesis for a lower extremity amputation will often include artificial foot and ankle components coupled to an upright assembly, which is in turn coupled to a custom-fitted socket assembly. If the amputation is an above the knee, the upright assembly will often include an artificial knee joint.
Often times, a cosmetic cover is fabricated to cover the endoskeletal components of the prosthetic limb described above to simulate the outward appearance of a "sound" limb.
Typically a cosmetic cover is fabricated by, first, taking circumferential measurements of the sound limb, typically in increments of 1"-2", along the length of the sound limb which is representative of the entire length of the prosthesis. Other Circumferential measurements are also taken of the prosthesis in a similar manner. Based upon these measurements, a commercially available tubular cosmetic cover blank is selected. The length of the cover blank is adjusted to the desirable length of the finished cosmetic cover. The inner surface (the hollow bore) of the tubular cosmetic cover blank is manually (or semi-manually) carved such that it will fit intimately over the outer surfaces of the prosthesis, and in particular, the prosthetic socket. The cover is typically stretched over the prosthetic socket, to some degree, which increases the outer circumference of the cover. After stretching over the prosthetic socket, the cover is typically bonded to the outer surface of the prosthetic socket.
Once the bonding agent has cured, the outer surface of the cosmetic cover is then manually sanded, ground or carved to obtain the desirable incremental circumferences of the sound limb. This step requires skill and experience for efficient fabrication of a desirable or acceptable cosmesis. Next, the cosmetic cover is smoothed and finished. Finishing can involve stretching layers of nylon stockinettes over the cosmetic cover and bonding them proximally to the cover, or can involve the application of a spray finish to match the pigment of the sound limb.
As is evident by the above summary, a significant amount of trial-and-error is typically required in fabricating the cosmetic cover from the tubular cosmetic cover blank. For example, the inner surfaces of the cosmetic cover are typically carved without consideration of any adjustments that may need to be made to the socket and/or endoskeletal components of the prosthetic limb. Thus, after the socket has been created and the prosthetic limb is assembled with the endoskeletal components and then fitted, adjusted and aligned on the amputee, the cosmetic cover will, at first, often not fit properly to the aligned and fitted prosthetic limb; requiring further modifications to, or a complete refabrication of, the cosmetic cover. With transfemoral (above the knee) amputees, this first cosmetic cover will often cause undesirable resistance to flexion and extension in the prosthetic limb, requiring further adjustment to, or a complete refabrication of, the cosmetic cover.
Furthermore, present cosmetic covers are fabricated out of a single-piece tubular cover blank (some manufacturers offer "discontinuous" covers having separate thigh and calf sections; however, each section remains a single piece). A disadvantage with the single-piece cosmetic covers, is that if access to the endoskeletal components is needed after the cosmetic cover has been mounted over the prosthetic limb (i.e., to make adjustments to the endoskeletal components), the cosmetic cover usually has to be cut or pulled down which will typically cause damage to the cover, and will sometimes require the entire cover to be refabricated. Also, because the cover is typically stretched over the prosthesis, circumferential tension will often cause small cuts in the cover to progress into large splits or tears.
Accordingly, a need exists for a system and method to precisely represent the prosthetic socket, limb, endoskeletal components and alignment of these items such that a cosmetic cover can be precisely milled based upon these characteristics; a need exists for a system that substantially automates the fabrication process of the cosmetic covers and that is sufficiently precise; and a need exists for a cosmetic cover that is easily fabricated and is also easily donned and removed from the prosthetic limb.